Several alkaloids obtainable from ergot (Clairups purpurea) such as ergocristine, to the unspecified stereoisomers of which the systematic name Ergoline - 8.beta. -carboxamide, has been attributed, and dihydro derivatives therefrom are also known in the art and have been investigated as to their pharmacological properties. The dihydro derivatives, such as 9, 10-dihydroergocristine, appear to be pharmacologically very active and show properties such as central vasodilation, anti-adrenalin action and to affect the heart and central nervous system. It has been suggested that these properties include cerebral vasodilation or vasoconstrictor dependent on dosage and decrease in oxygen demand. Experimental work showed that the amounts of blood flowing through the arteries to the brains through the carotid arteries (arteriae carotes) and through the vertebral arteries (arteriae ventrales) are slightly diminishing, whereas the blood pressure of the maxillary veins (venae maxillares) initially decreases superficially, which is followed by an increase. Respiration was hardly affected.
Vincamine, an alkaloid obtainable from periwinkle (Vinca Minor L), to the unspecified stereoisomers of which the systematic name 1H-Indolo [3,2,1-de] pyrido[3,2,1 -ij] [1,5] naphthyridine - 12 - carboxylic acid has been attributed and derivatives thereof as e.g. vincamone to which the name 13.alpha. -ethyl-2,3,6,13,13a,13b-hexhydro-1H-indolo [3,2,1-de] pyrido [3,2,1-ij] [1,5] naphthyridin-12 (5H)-one has been attributed, and their salts are also known in the art and several pharmacological properties have been reported.
The above compounds are referred to below as vincamines or a vincamine. A cardiovascular action and cerebral vasodilation increasing cerebral blood circulation have been reported. Experimental work showed that the compound has a slight initial hypotensive effect on the arteries which is followed by a very slight hypertensive action. The flow of blood through the arteries is hardly affected but a tendency towards increase might be noticed. However, the flow of blood returning from the brains via the veins is increased, indicating an increased blood irrigation of the brains.